Disclosed is a distributed battery management system that uses cell modules that are attached to cell terminals. A connector tab extends from the cell modules that provides a solid thermal and electrical connection to a cell terminal, as well as structural support for the cell module. A single wire is used to connect the cell modules that carries power, a voltage sample level, a serial data stream, indicating the temperature at a cell terminal to which the cell module is connected, and voltage level of each of the cells, as well as discharge current to equalize the charge of each of the cells. Various adapters can be used for different cell formats, which provide structural support for the cell modules. Reverse connection protection circuitry is also provided that protects the circuitry in the cell modules from accidental reverse connection.